1. Field of the Invention
This invention relates to a process for making a crumb silicone material.
2. Background Information
Making silicone materials into crumbs or powder is known in the art. The most difficult solid silicone materials to make into powders or crumb are the deformable, flexible material such as the elastomeric materials. Hard and brittle materials can be ground but the flexible materials do not lend themselves to being ground by ordinary techniques. Elastomeric materials can be divided or made into particulate material by sheeting and cutting into small pieces or by shearing under very high shear. Another technique which has been used is to reduce the temperature below its glass transition temperature and then grinding or dividing it some other way. These techniques are suitable to make the materials into particles but are expensive and difficult to do. For example, with the glass transition temperature for some silicone materials at -120.degree. C., cryogenic methods are required. Bruner in U.S. Pat. No. 3,843,601, issued Oct. 22, 1974, teaches that a silicone elastomer made by curing a vinyl containing polymethylsiloxane with a vinyl specific peroxide can be crumbled into a powder under high shear stress conditions. These high shear stress conditions require special shearing apparatus to generate the proper shearing action and as a result are expensive or limited in the kinds of materials which can be used to make the powder.